Long traffic jams are being reported on the M25 in the evening rush hour after a crash closed two lanes.
The disruption is reported clockwise from J26 A121 Honey Lane (Waltham Abbey) to J27 M11 J6 with two lanes remaining closed, after traffic was briefly held.
Meanwhile there are severe delays on the Central line between Northolt and West Ruislip due to an earlier points failure at Ruislip Gardens.
There are also severe delays between Stratford and Richmond and Clapham Junction on London Overground due to an earlier points failure.The Gatwick Express and Southern services were earlier hit by delays due to a defective track near the airport.
A 20mph speed restriction was in place on one of the two northbound lines between Gatwick Airport and Redhill.
